The present invention relates to a magnetic disk drive, and more particularly to airflow control within the enclosure thereof.
Data storage devices using various types of media such as optical disks and magnetic tapes are known. Among them, hard disk drives (HDDs) have become popular as storage devices for computers to such an extent that they are one type of the storage devices indispensable for today's computers. Further, not limited to computers, HDDs are expanding more and more in application because of its excellent characteristics. For example, HDDs are used for moving picture recording/reproducing devices, car navigation systems, cellular phones, removable memories used in digital cameras and so on.
Each magnetic disk used in HDDs has a plurality of tracks formed concentrically and each track is partitioned into a plurality of sectors. Servo data and user data are stored in each sector. A spindle motor rotates a magnetic disk, and a head element as a thin film element makes access to a desired address position in accordance with the servo data of a sector, whereby it is possible to effect write or read of data to or from the magnetic disk.
A head element portion is fixed to a slider, both constituting a head. The slider is adapted to fly over a rotating magnetic disk, whereby the head or head element can be moved to a desired position over the magnetic disk. In a data read operation, a signal read from the magnetic disk by the head element is subjected to predetermined signal processing such as waveform shaping or decoding in a signal processing circuit and is sent to the host. Data transferred from the host is subjected to predetermined signal processing in the signal processing circuit and is then written to the magnetic disk.
In HDDs, an airflow generated by the rotation of the magnetic disk poses a problem. For example, the airflow flutters the actuator to impair accurate positioning of the head. To overcome this disadvantage, Patent Document 1 (Japanese Patent Laid-open No. 2002-133827) discloses an example in which a bypass channel through which the airflow passes is provided between a ramp and the sidewall of a base.
In addition thereto, fluttering of the magnetic disk (disk flutter) caused by the turbulence of the airflow generated by the rotation of the magnetic disk poses a problem. The disk flutter impairs accurate positioning of the head to the track, similarly to the flutter of the head itself. In particular, as the recording density of the magnetic disk increases so that TPI (Track Per Inch) becomes high, more accurate positioning of the head is required, and even a slight disk flutter poses a problem.